Electric furnace.



il l) Al Q UNITED vSTATES PATENT ernten.

HUBERT HOFF, F DDELINGEN, LUXEMBURG, ASSIGNOR IJO EISENHUTTEN`ACTIEN- VEREIN DDELINGEN, OF DPELINGEN, LUXEMBURG.

ELECTRIC rcnimonf specifiatior. of Letters Patent.

Patented Feb. 14, 1911.

Application filed September 2 5, '1909. Serial No. 513,638.

To all whom it may concern:

Be it known that l, HUBERT Horn, a citizen of the German Empire, and residing at Diidelingen, in the Grand Duchy of LuxeniM burg, have invented certain new and useful Improvements in Electric Furnaces, of which the following is a specification.

My invention relates to a combined urnace for treating substances with heat especially :for chemical and metallurgical purposes, such as the production of glass or the falcination of ores or minerals, or the extraem tion or refining of metals andthe like. The object of my inventionis to provide a urnace in which great heat in the cheapest porsible, manner may be produced, and l eitect this by a combination of electricv heating with a eoaledust, furnace.

'The employment on lthe one hand of the maal-dust furnace alone and on the other hand of the electricheating device for carrying outfthe processes mentioned above is al: ready known. The electric heating enables any desired high temperatures to be obtained, but electric energy is relatively expensive, so that the employment of electric heating' alone is only profitable in connection with a small number of processes. ,Many attempts have been made to combine electric heating with other methods of heating, for example heatii'ig by gas in hearth furnaces, buteyen 'i this case a very large expenditure of electric energy yin necessary, or other diiiicultiee occur.

`When a Well arranged system of heating` with coal-dust is combined. With a system oit electric heating an exceedingly high temperature is; already obtained by the coal-dust heating', so that. it is only neceseary for the electric heating to begin in the last stage of the process and the greatest part of the necessai'y heat is produced by the consumption ol',E coal, that is in an inexpensive Way.

l l:till describe iny invention pa1.;icularlyy in connectioi'i \,.f'ith the production of ingetiron or steel.

The furnace which l preferably employ is illustrated in the accompanying drawing, i whiclr- Figure 1 is a longitudinal section through the line B B in Fig. Q, and Fig. Q, a trainm verse section through the line A A in. Fig. i. a is the body of a. l'iearth furnace, which is reinforced with steel Sheet 7o. Side of the furnace anoblique passage c i1n- On the "one ping-es, which is closed by a coi/er al through which the pipe e of a Wind-pressure conduit runs. This conduit is supplied with air under pressure by ineens or' the blower f, and 'terminates in the passage c with a nozzle g. Ohliquely on the pipe c a; second pipe i arranged, which conveys coal-dust, ldrawn from any suitable reservoir (not shown in the drawing).

For the electric heat-'ing two electrodes el, z' are provided', which run through the top la of 'the furnace into the slag orthe bath.

0n the side of the furnace situated. opposite to the passage c, isa tine pipe @which conveys the combustion gases into the chimney.

The burners c, f7 as Well :'isthe electrodes and the tine pine l can be removed from the sid-ea of the furnace.

The furnace is suitably ypivoted on Jthe 'foundation by means of bent bars m and furnishedon the side with a spoutl n., so thatv it can be tilted by means of a suitable niechal nisni and he emptied.

The combined electric and coal-duet furnace .is used as follows: I put the material to be heated., for example iron` scrap and the usual additional substances on the hearth of the itfnrnace. l'then set the coal-dust lire in action, regulatii the quantities of air and coal-dust by nie: s oit suitable devices. The thune produced melts the materials and inconsequence of the iitalily high temperature they act onone another. When this action has been effected to a suilicient extent, forexainile -when only small percentage of iinthe coalalnst lire. l remore the coal-.dust burner and likewise the ine-pipe l from the furnace and close the openings thereby made by Ineans oit doors which are reinforced .s0 as to be lire-proof. then switch on the current. which 'l convey by means'of the electrodes 1"., if through the slag" floating `on the bath. The, 'strengtlfi of the current inay be. automatically and permanently regulated,

till contained in the steel, I stopy for example 'according to the Well known Thury system. Any other regulating 'arrangement may however be employed, for

'example regulating: by hand.

l desire to point out that my invention i` not Arest furnace. Any type ojeoahdust 'orelectr furnace may be employed.

to the con'ibination of a par f tisular coal-dust 'with a particular electrir` My inpryedffnrnace is hardly larger than` any of the known electric furnaces, and can he made at almost the same price as such. The costs for installing the requisite hnrner, for introducing the air of comonsiion ini'o the furnace, as well as those for installing' the apparatus for regulating the supply of coal-dust are exceedingly small compared with those incurred for example in connection with a Martin plant and its accessories.

As already mentioned, the improved furnace is suitable for the most varied chemical and rneiiallurgicaloperations, for which high i'emperaures are necessary.`

Having thus described my invention, what I claim as new and desire to @over ny nel'- ters Patent 1s:-

In an electric furnace the combination of' an open hearth. a passage (Amendingv at a' slantfroln said hearth. Closing means for said passage, a conduit projecting' info .said passage for conveying air into Hte in'nare. and a pipe for conveying eoalflnsi opening! into said conduit.

In Witness whereof l have herenni'o sei my hand in presence of two Witnesses.

A. M. S'rnoUrUL, vJnssnnnli Catimini. 

